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2585 :: Macro: enumerate exported functions from a module

• jlp765 (orginal) [2016-10-21T02:52:50+02:00] view original

  Is it possible to enumerate the procs exported from a library, and has anyone got some example code of anything similar to this?

  I have a template/macro that hoists math functions to apply them to seq[seq[]], and was wanting to do this generically for the exported math procs, rather than as hard-wired calls for each exported proc.

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• flyx (orginal) [2016-10-21T08:14:50+02:00] view original

  If you write the module yourself, the simplest way would be:

  macro myMacro(body: typed): typed =
    # do things here
    #
    # do not forget to add the original procs to the output!
  
  myMacro:
    proc proc1*() = discard
    proc proc2*() = discard
    
    # ...
  Run

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• Arrrrrrrrr (orginal) [2016-10-21T08:54:13+02:00] view original

  You can also use myMacro as pragma: proc proc1*(){.myMacro.} = discard. I don't know why you cannot push/pop custom macros on the other hand. That would be useful for modules.

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• Araq (orginal) [2016-10-21T09:12:02+02:00] view original

  Well jlp765 asked about math.nim in particular which requires something like parseStmt(staticRead"lib/pure/math.nim").

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• flyx (orginal) [2016-10-21T09:20:45+02:00] view original

  Wow, I never thought of that. With this, we can write fuckit.nim!

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• andrea (orginal) [2016-10-21T11:44:05+02:00] view original

  I guess the use case is similar to this

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• jlp765 (orginal) [2016-10-21T15:00:20+02:00] view original

  @Andrea, I was asking, to see if there was a way of avoiding manual enumeration of proc names, like at the bottom of your example.

  If a new proc is added to the math lib, then you manually have to add it to your lib :-(

  
  makeUniversal(sqrt)
  makeUniversal(cbrt)
  makeUniversal(log10)
  makeUniversal(log2)
  makeUniversal(log)
  makeUniversal(exp)
  makeUniversal(arccos)
  makeUniversal(arcsin)
  makeUniversal(arctan)
  makeUniversal(cos)
  makeUniversal(cosh)
  makeUniversal(sin)
  makeUniversal(sinh)
  makeUniversal(tan)
  makeUniversal(tanh)
  makeUniversal(erf)
  makeUniversal(erfc)
  makeUniversal(lgamma)
  makeUniversal(tgamma)
  makeUniversal(trunc)
  makeUniversal(floor)
  makeUniversal(ceil)
  makeUniversal(degToRad)
  makeUniversal(radToDeg)
  Run

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• andrea (orginal) [2016-10-21T15:16:19+02:00] view original

  Yes, I agree that manual enumeration is not nice. I was just giving some context where this could come up :-)

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• jlp765 (orginal) [2016-10-21T15:20:56+02:00] view original

  Ok, I will fess up.

  I was really thinking that collections like linked lists, queues, rings, ....

  where it would be nice if there was a lib you could import, which hoisted lib procs (applied by iteration thru each element),

  something like

  
  import queues, math
  import hoisting
  
  hoistLibProcs("queues", "math")   # <- this would make procs from math work with queues
  
  var q: Queue
  #
  # do setup of queue data here
  #
  
  let sq = q.sqrt()  # this would take the sqrt() for each element of q (because sqrt() has been hoisted)
  Run

  Advantages:

  • users choice as to whether hoist proc from a lib (can hard-wire their own if they want to)
  • don't have to go through enumerating procs from a lib (matches future changes in hoisted lib)
  • apply to any collection type provided there is a standard collection iterator (??)

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• andrea (orginal) [2016-10-21T16:05:49+02:00] view original

  Well, in fact if any collection supported map, you could just do coll.map(f) at the usage site. Actually, I find this clearer

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• jlp765 (orginal) [2016-10-22T08:00:16+02:00] view original

  It appears that only the sets module has a map function.

  Sounds like a good improvement to the other collection types :-)

  Of course, converting to a seq[] first means the normal map() can be used.

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